1. Field of the Invention
The invention relates to the field of waste water treatment with hydrophilic dispersion polymers.
2. Description of the Prior Art
Water soluble copolymers of acrylamide and cationic monomers such as dimethylaminoethylacrylate methyl chloride quaternary salts are well known in the literature. U.S. Pat. No. 3,647,769 teaches the formation of a copolymer of acrylamide and acrylonitirile followed by reaction with amines. Polymers of this type have high molecular weights, high viscosities in water and are hydrophilic. However, to ship such aqueous polymers in commerce, very dilute solutions would be required which is impractical. Preparation of inverse latex polymers or water-in-oil emulsions is described in U.S. Pat. No. 4,391,932. The inverse latex product is an oil continuous phase with water soluble polymer particles dispersed within the oil by emulsifiers. Activation of these polymers can require sophisticated equipment and often the polymer particles are not completely solubilized.
Water dispersions polymers described as water soluble co- and terpolymers containing a hydrophobic moiety are described in U.S. Pat. No. 5,006,590 and U.S. Pat. No. 4,929,655, assigned to Kyoritsu Yuki Co., Ltd., Tokyo, Japan. Disclosures of these patents are incorporated herein. These polymers are prepared in a water continuous phase containing salts and in some cases low molecular weight cationic polymeric dispersants. The polymers are diluted in water for activation. In these polymers the hydrophobic moiety prevent the polymer from fully solubilizing and reaching full activity. According to those inventions, the polymer dispersion is prepared from a water-soluble monomer mixture containing at least 5 mole percent of a cationic monomer represented by the general formula (I): ##STR1## where R.sub.1 is H or CH.sub.3 ; R.sub.2 and R.sub.3 are each an alkyl group having 1 or 2 carbons atoms; A.sub.1 is an oxygen atom or NH; B.sub.1 is an alkyl group and X.sub.1 is a counter anion such as chloride or bromide.